The only reason I can think of to get it, is if you have no
desire to learn how to tune your car yourself.
I took a look at one of these at the last SEMA show. It's very pretty, displays some cool stuff, and gives you the ability to flash the stock ECU only with Cobb's maps available for download.
When I spoke to them about it, and maybe I misunderstood the rep., but it still gave the individual no control over timing and fuel and only Cobb authorized tuners will be able to customize maps and tables.
... and how much will these authorized guys charge?
... and it starts at $695!
I'll put that towards a used laptop ($300), cable ($90), evoscan ($25), and a wideband ($200), but that's just me.